1. Field of the Invention
This invention relates to a method for inspecting resistance exerted to photographic film accommodated in a magazine when the photographic film is drawn out from the magazine, and an apparatus for carrying out the method.
2. Description of the Prior Art
As is well known, photographic film such as 35 mm film is wound around a spool in a magazine and thus accommodated in the magazine for use in photographing in cameras. However, in cases where, for example, the spool and the magazine are not coupled correctly, large resisting force is exerted to the film when the film is drawn out from the magazine. If the resistance to film draw-out is very high the film would break when it is drawn out from the magazine and wound up around wind-up shaft of a camera. Therefore, after the film has been accommodated in the magazine in the film production process, the resistance to film draw-out has heretofore been measured in order to regard the magazine defective when the measured resistance to film draw-out is higher than a predetermined value.
One of the apparatuses for inspecting the resistance to film draw-out has been disclosed in, for example, Japanese Unexamined Patent Publication No. 58(1983)-71737. The disclosed apparatus holds a magazine, pulls a film leader, which has been drawn out from the magazine, in order to further draw out the film leader from the magazine, and measures the force required to draw out the film leader.
However, in many cases, the film has not been tightly wound around the spool in the magazine before the resistance to film draw-out is measured. Therefore, with the disclosed apparatus for inspecting resistance to film draw out, the spool does not often rotate when the film leader is drawn out from the magazine in order to inspect the resistance to film draw-out. As a result, during the inspection of the resistance to film draw-out, only the resistance to sliding of the film along the film outlet of the magazine is measured, and it is not possible to inspect whether or not the spool rotates lightly. In order to eliminate this problem, the film leader may be drawn out until the spool is rotated. However, in such cases, even the film portion which follows the film leader and which is to be actually used to take photographs is drawn out from the magazine, and therefore the film must be rewound around the spool after the resistance to film draw-out has been inspected.